The invention relates to a heat exchanger, a cooling system and method for operating a heating exchanger and a cooling system.
EP 1 902 950 B1 describes an avionics cooling system for an aircraft. By means of a heat exchanger, an avionics liquid cooling circuit transfers the heat generated by an avionics unit to a fuel flow in a fuel circuit disposed entirely inside a fuel tank. A vapor cooling circuit discharges the heat from the fuel circuit by means of an evaporator. The coolant evaporated inside the vapor cooling circuit is condensed in a ram-air cooler disposed outside of the fuel tank, the heat being transferred from the coolant to the ram air.
In an aircraft air-conditioning system, bleed air required for air-conditioning an aircraft passenger cabin can be drawn from a high-pressure compressor of an engine, and the temperature of the bleed air can be reduced by means of a pre-heat exchanger, before the bleed air is fed to an air-conditioning set for the purpose of further cooling.
As an alternative to such a system architecture based on drawing bleed air from an engine, it is conceivable to have a system architecture of an aircraft air conditioning system in which the air required for air-conditioning a passenger cabin is not drawn from an engine of the aircraft, but is fed into the aircraft from the environment of the aircraft, via an air inlet provided in the aircraft fuselage, and is then compressed and cooled by means of an electrically operated compression and conditioning system. However, the compression and conditioning system generates waste heat, which has to be discharged from the aircraft by means of a suitable cooling system.